The producers of Spain’s renowned manchego cheese have accused their Mexican counterparts of “crude plagiarism” in a row that is holding back a new trade deal between the EU and Mexico.

“We have to defend our manchego tooth and nail,” says Francisco Tejado, walking through the factory of Spain’s biggest cheese producer, Garcia Baquero, located in the arid plains of La Mancha, the region famed for the cheese.

Manchego is an EU protected designation of origin (AOC) product, which is respected within the bloc but not always further afield.

And in Mexico, in particular, manufacturers have used the names of several “European cheeses, including manchego, to reap profit from crude plagiarism”, complains Santiago Altares, head of the group that gives out AOC labels to manchego producers.

The original and the copy, he stresses, are completely different. “The Mexican manchego is made from cow’s milk within seven days, and the authentic manchego with the milk of ewes of manchega race, is ripened for at least a month.”

Such is the controversy over the matter that it has been one of the issues in talks aimed at sealing a new version of an 18-year-old trade deal between the EU and Mexico. The Europeans want exclusive right to the “manchego” name, along with other products.

But that is a problem for cheese producers in Latin America’s second-largest economy, where Mexican manchego represents nearly 15% of total cheese sales. So the National Chamber of Dairy Industries in Mexico has said it will continue using “manchego” as a name, which it says is “generic”.

“But for us, this protection of manchego as an AOC product is of utmost importance in a semi-arid, austere, under-populated region,” says Miguel Angel Garcia Baquero, the head of the eponymous cheese producer. “We can’t lose the little we have.”

More than 700 Spanish farmers and 65 producers depend on the cheese for their livelihood. Every year more than 15,000 tonnes of manchego are produced, with 60% of that exported.

Paqui Diaz Pintado Borja, head of the family-owned La Caseta producer, says: “Our manchego is artisanal because it is made from unpasteurised milk.” Her son Antonio Araque says the manchega ewes “have less wool than the others, no horns, but provide a better quality milk, rich in protein”.

He wants a ban on using the name manchego in Mexico but acknowledges “it’s going to be complicated because there are many interests at play in give-and-take negotiations” with the EU.